Cave of Crystals "Giant Crystal Cave" at Naica - Mexico

Mexico's Giant Crystal Cave Is Beautiful But Deadly, Discovered by chance, the secret Mexican crystal caves big enough to drive a car through The Cave of Crystals, also known as the Giant Crystal Cave, is a cave connected to the Naica Mine at a depth of 300 meters (980 ft) in Naica, Chihuahua, Mexico. It takes the form of a chamber within the limestone host rock of the mine, and is about 109 meters (358 ft) long with a volume of 5,000 to 6,000 cubic meters (180,000 to 210,000 cu ft). The chamber contains giant selenite crystals (gypsum, CaSO₄·2H₂O.), some of the largest natural crystals ever found. The largest is 11.40 meters (37.4 ft), with a volume of about 5 cubic meters (180 cu ft), and an estimated mass of 12 tonnes.